Fluorosulfonic acid treatment of hexachlorocyclopentadiene



Patented May 15, 1951 FLUOROSULFONIC ACID TREATMENT OFHEXACHLOROCYCLOPENTADIENE Earl T. McBee and Jack S. Newcomer, WestLafayette, Ind., assignors to Purdue Research Foundation, WestLafayette, Ind., a corporation of Indiana No Drawing. ApplicationOctober 1, 1948, Serial No. 52,409

6 Claims.

ing pentachlorocyclopentenone, (22) reduction of ahexachlorocyclopentenone of melting point 92 degrees centigrade withstannous chloride, (c) reduction of a hexachlorocyclopentenone ofmelting point 28 degrees centigrade with stannous chloride, and othermethods, all of which are based on degradation to apentachlorocyclopentenone, dehydrochlorination, and dimeriza tion of theresulting tetrachlorocyclopentadienone.

It is an object of the present invention, therefore, to eliminate thestep of forming a ketone in the preparation ofoctachloro-3a,4,7,7a-tetra hydro-4,7-methanoindene-1,8-dione from hexachlorocyclopentadiene. It is a further object of this invention toproduce octachloro-3a,4,7,7atetrahydro-4,7-methanoindene-1,8-dionedirectly from hexachlorocyclopentadiene in a single step. Another objectof the invention is the provision of a novel process for the treatmentof hexachlorocyclopentadiene with fluorosulfonic acid. Other objectswill become apparent hereinafter.

The compound produced by the method of the present invention is animportant intermediate in the preparation of more complex organicmolecules, such as perchloroindone, which may be subsequently convertedto terachlorophthalic anhydride, a valuable constituent in thepreparation of resins of the glyceryl phthalate type.

The process of the present invention includes the reaction offiuorosulfonic acid with hexachlorocyclopentadiene. The result of ournew process was not to be expected, since such is not obtained by thereaction of hexachlorocyclopentadiene and chlorosulfonic acid. Thereaction can be performed in any suitable manner, such as by adding thefiuorosulfonic acid to the hexachlorocyclopentadiene, the reverseprocedure also being entirely satisfactory. Agitation is helpful inassuring efficient contact of the reactants. The reaction temperatureusually employed is between about 60 degrees and about 140 degreescentigrade, with the optimum temperature being between about degrees andabout 120 degrees centigrade, although others may be used if desired. Itis, in most instances, preferable to add the fluorosulfonic acid to thehexachlorocyclopentadiene portionwise with stirring to avoid loss ofreactants and reaction products which may occur with exothermicreactions. The time allowed for reaction is of secondary importance,since the reaction appears to be substantially instantaneous. However,reaction periods of from about one-half hour to several days may beemployed, with the shorter periods being, of course, most desirable. Theratio of reactants is not critical, and while about equimolarproportions are generally employed, an excess of either is notdisadvantageous, and in some instances an advantage may even be gainedby employment of an excess of one reactant or the other. The reactionmay be conducted in the presence or absence of a liquid organic solventwhich is inert to the reactants and reaction products under conditionsof reaction. The octachloro-tetrahydro-methanoindene-dione, either asthe anhydrous or hydrous form, maybe separated from the reaction productand purified in any conventional manner, such as by recrystallization,which will be apparent to one skilled in the art. The hydrate isobtained if water is present in the reaction mixture or is contactedwith the reaction product, and the anhydrous form may be obtained fromthe hydrate by recrystallization from an organic solvent. The anhydrousform is obtained directly when an organic solvent is used forcrystallization of the reaction product.

The following example is given to illustrate the practice of thisinvention but is not, however, to be construed as limiting.

The anhydrous form of octachloro-3a:,4,7,7atetrahydro 4,7 methanoindene1,8 dione was prepared by adding 400 grams of fluorosulfonic acid to544. grams of hexachlorocyclopentadiene during a period of two hours at80 to degrees centigrade, dropping the reaction mixture into water toobtain the hydrate, and recrystallizing the hydrate from petroleum etherto obtain the anhydrous product.

The equipment consisted of a stainless steel beaker of about one-galloncapacity equipped with a motor-driven stirrer, thermometer, and droppingfunnel. Profusive fuming occurred throughout the reaction, The crudeorange-red liquid product was poured onto ice and washed three timeswith water, the liquid becoming thicker after each washing. The finalwashing Various modifications may be made in themethod of the presentinvention without departing from the spirit or scope thereof, and it.

is to be understood that we limit ourselves only as defined in theappended c1aims.

We claim:

1. The method which includes: mixing together hexachlorocyclopentadieneand fluorosulfonic acid and heating the reaction mixture to causereaction between the hexachlorocyclopentadiene and the fluorosulfonicacid to produce octachl'oro 3a,4=,7,7a tetrahydro 4,7methanoindene-l,8dione.

2. The method which includes: mixing to.-

"gether hexachlorocyclopentadiene and fluorosulfonic acid and heatingthe mixture at a temperature between about 60 degrees and 140 degreescentigrade to produce octachloro-3a,4,7,7atetrahydro 4,7 methanoindene-.l,8 dione, and separating octachloro-3a,4 ,7,7aetetrahydro-4,'7'-methanoindene-l,S-dione from the reaction product.

3. The method of claim 2, wherein the reaction product is contacted withwater and octa chloro 3a,4,7,7a tetrahydro 4,7 methanoindene-l,8-dionehydrate separated.

4. The method which includes: mixing together, at a temperature betweenabout degrees and about 140 degrees centigrade,hexachlorocyclopentadiene and fluorosulfonic acid, to. produceoctachloro-3a,4,7,7a-tetrahydro-4,7- methanoindene-LB-dione.

5. The method of claim 4, wherein the temperature is between aboutdegrees and about degrees Centigrade.

6. The method of claim 4, wherein the fluorosulfonic acid is addedportionwise to the hexachlorocyclopen a i ne- EARL T. MoBEE. JACK S.NEWCOMER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Bockemuller Nov. 14, 1939 OTHER.REFERENCES Prins Rec. Trav. Chim., vol. 65, pages 455, to 467 (1946)Zincke et al. Annalen, vol. 367, pages 1 to 13 (1909).

Number

1. THE METHOD WHICH INCLUDES: MIXING TOGETHER HEXACHLOROCYCLOPENTADIENEAND FLUOROSULFONIC ACID AND HEATING THE REACTION MIXTURE TO CAUSEREACTION BETWEEN THE HEXACHLOROCYCLOPENTADIENE AND THE FLUOROSULFONICACID TO PRODUCE OCTACHLORO - 3A,4,7,7A - TETRAHYDRO -4,7METHANOINDENE-1,8-DIONE.